[LG Optimus 3D] boltthrower56:
Hello guys ;

I didn't see anything like it , so i decided to make a guide for a portable charger.

This is especially handy if you have leftover batteries from old phones , you can't use them on your new phone but they still function. Why throw them away ?

Instead you can make a portable charger with it. Even AA ones will work. (Rechargeable recommended but not necessary)

You would pay 30-40 dollars for a portable charger with 5200 Mah capacity , What I'm offering is 12 Dollars for 7000 Mah Capacity.

So , It's practical , has a low cost , easy to make , has a high efficiency and if you have a little creativity it would look great.

First you need to understand the mechanics of a lithium-ion battery (Which we use)

It consists of a lithium ion solution , an anode and a cathode floating in the solution.

Lithium ions will move from negative (Cathode) to positive (Anode) taking electrons from lithium ions in the process , thus making it neutral.

This process is reversed by charging , delivering a desired current to lithium atoms will ionize the solution and making the neutral atoms , ions once again.

The current always flows from higher voltage to lower voltage , that's why the chargers are usually rated 4.8-5.0 volts in the chargers , instead of 3.7 like the battery.

If you use 3.7 volts in the charger the current will not flow , it will balance and it will not charge.

Dump charging means charging a battery at a higher rate than the phone allows by using batteries.

P920 will not accept currents higher than 1 amp so you will not be able to dump charge your battery using the charge slot , instead you will use the wires to connect the charger to your battery in the right polarity.

you will need to hold it by hand but no worries the process takes about 30 seconds to charge it from 0% to %50...

It decreases the life expectancy of the batteries so use it just for urgent matters.

So this is all you need to know so far as mechanics are the concern.

Prerequisites ;

Two batteries (Can be ordered from ebay , 3.7 volts 3500 mah , perfect for a portable charger) (You can use only one. In that case , skip the first step)

Insulated copper wires (Can be obtained or salvaged from anywhere , quality ones will improve the current)

A Step-up regulator (Can be bought from ebay , link will be given)

A custom made case (Optional , You can use electric tape to seal it instead)

A soldering iron

Solder

1. Connect the batteries in parallel ;

Take a copper wire and solder it to one of the batteries' negative terminal and to the other battery's negative terminal.

Take another copper wire and solder it to the positive terminal of one of the batteries and to the other battery's positive terminal.

Now you've wired the batteries in parallel.

It will not increase the voltage instead it will couple the "Mah" ratings and the current.

2. Take out the Step up regulator and wire it to the batteries in parallel ;

Take a wire and solder it to the negative side of the batteries in parallel (Doesn't matter which but we will use that battery one from now on.) and to the step-up regulator's negative side (It's marked on the pcb)

Take another wire and solder it to the positive side of the battery (the battery you just soldered the negative side to) and to the positive side of the step-up regulator.

And poof , you just made a portable charger.

You can connect it to your phone using the usb female output plug on the step up regulator.

Now it's time to make a case for it or you could just use electrical tape to seal it off. (That's what i did)

What we did (In short) ;

We wired 2 batteries in parallel and made the current 3.7 volts and 7000 Mah.

Then we used a DC to DC Step-up Regulator to increase the voltage to 5 volts to promote the flow of current from the charger to the battery.

Then we built a case to put the charger in or we used electrical tape to seal it.

Notes and Advice ;

Cut the insulation on the wires short , otherwise you can short-circuit the terminals. (Or use hot glue on them)

Take a drop of solder and drop it to the battery terminal using the soldering iron it's enough to make the wire stick to the terminal.

Coat the wires with solder before soldering.

The polarizations on the terminals are marked on the battery sticker. (The ones that are not marked are "Ground" terminals)

The polarizations on the step-up regulator are marked on the step-up regulator's pcb (Printed Circuit Board)

Do not short circuit the terminals , ever. (Use hot glue to make sure) (Optional)

You can use any DC battery rated 3.7 volts for this. They are as cheap as 2.50$ for a 3600 Mah rated one

If you don't use the step-up regulator , you will charge slowly and only when the battery on the phone has %30 or less charge remaining.

If you have a question , please ask.

If you have a webcam or video camera , i can remotely help you build it.

If you think i missed anything , leave a comment and i will edit.

I made mine before i decided to make this guide so i will not be providing a video for it , but the users of this guide are welcome to make a video for it , i can put it on my post.

With the links i gave , it costs about 20 dollars to make , it has a 7000 Mah rating more than any portable charger will give.If you use one battery it's 12 dollars. If you use other batteries on ebay it can cost as low as 9 Dollars for 7200 Mah rated charger.

The cheaper ones on the ebay will work just as well.

Links :

http://www.ebay.com/itm/3500mAh-Ext...522605?pt=PDA_Accessories&hash=item27c6c4faed (Extended battery and it's back cover)

http://www.ebay.com/itm/370718295020?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 (Step-up regulator , rated 5 volts)

http://www.ebay.com/itm/3-6V-3600mA...802080332?pt=UK_Batteries&hash=item4609337e4c (A 3600 Mah battery 2.84$ great for it.)

Good Luck.

Cheers!